Thread 사용법

* MainActivity.java

public class MainActivity extends AppCompatActivity {

    TextView textView;
    Handler handler = new Handler();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textView = findViewById(R.id.textView);

        Button button = findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                BackgroundThread thread = new BackgroundThread();
                thread.start();
            }
        });
    }

    class BackgroundThread extends Thread {
        int value = 0;

        public void run() {
            for (int i = 0; i < 100; i++) {
                try {
                    Thread.sleep(1000);
                } catch (Exception e) {
                    //
                }

                value++;
                Log.d("MyThread", "value : " + value);

                handler.post(new Runnable() {
                    @Override
                    public void run() {
                        textView.setText("값 : " + value);

                    }
                });

                handler.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        textView.setText("값 : " + value);
                    }
                }, 5000);
            }
        }
    }

}